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AF incidence up 3% annually in community-based study

JAMA Network Open
Reuters Health - 02/09/2020 - Atrial fibrillation (AF) incidence rates increased by 3% a year from 2006 to 2018, according to a new study from one integrated healthcare-delivery system.

"Our results show increasing AF across the board - all age groups, inpatient and outpatient settings, primary vs. secondary diagnosis. This suggests a global increased tendency to diagnose and document AF across all clinical settings," said Dr. Brent A. Williams of Geisinger Health System in Danville, Pennsylvania.

"Our study did find increasing AF risk factors and more short-term electrocardiogram (ECG) use in at-risk populations, but these do not appear to explain the majority of the increase," he told Reuters Health by email.

While the burden of AF is growing, the reasons behind the increase aren't fully understood. To investigate, Dr. Williams and his team looked at more than 500,000 patients from their health system, 22,077 of whom developed AF.

From 2006 to 2018, standardized AF incidence rose from 4.74 to 6.82 cases per 1,000 person-years (P<0.001), the researchers report in JAMA Network Open. People 85 and older accounted for 12.6% of incident AF cases in 2006 and 18.6% in 2018.

Over time, patients diagnosed with AF were more likely to have a high BMI (39.9% of patients in 2006-2008 vs. 48.9% in 2015-2018), hypertension (81.6% vs. 86.1%) and ischemic stroke (9.7% vs. 15.8%). Prevalence of coronary-artery disease in AF patients decreased, however, from 45.2% to 41.4%.

Among at-risk patients, documentation of short-term ECG increased from 11.2% in 2008 to 16.0% in 2017.

"Our results suggest that AF is simply being diagnosed and documented more through usual clinical channels than it previously was. If this is true, AF would increase at a faster rate among older people simply because they tend to utilize formal healthcare services more frequently, and thus have more opportunity to have AF uncovered," Dr. Williams said.

"A frequent complication of AF is ischemic stroke, and oral anticoagulation greatly reduces ischemic stroke risk in AF. So, finding previously latent AF might prevent stroke through proper treatment, but the challenge for physicians becomes in whom to look for AF and how," he added. "Detecting AF sometimes requires wearing monitoring devices for extended time periods which creates inconvenience and cost. Preventing more strokes from AF might be an attainable goal, but whether looking for AF more thoroughly (is a good idea) in the context of competing healthcare priorities is debatable."

Dr. Alonso Alvaro, a professor at the Rollins School of Public Health at Emory University in Atlanta who studies the epidemiology of AF, told Reuters Health by phone, "This kind of study shows the value of electronic health records for research."

"It will be interesting to know whether the patterns that we are seeing here are occurring in other areas and other groups," he added. "Trying to understand whether these patients are similar in other settings is important."

By Anne Harding

SOURCE: https://bit.ly/2GfDTob JAMA Network Open, online August 28, 2020.

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